The invention relates to fuel delivery systems, and more particularly, to marine fuel delivery systems including a fuel tank inside a boat, and means for supplying fuel from the fuel tank to the engine of a marine propulsion device mounted on the boat. through the fuel distribution system. This negative pressure, however, can cause the fuel to vaporize in the fuel supply line. The result can be inability of the fuel distribution system to supply liquid fuel to the engine at a given fuel flow rate due to excessive fuel vapor generation, often referred to as vapor lock.
A known method of preventing vapor lock is to pump the fuel under pressure through the fuel distribution system to the engine. Pumping the fuel under pressure will eliminate the tendency of the fuel to vaporize because it is at a positive pressure. However, leakage of a pressurized fuel line would allow fuel to leak into the bilge of a boat.
Attention is directed to Ellis U.S. Pat. No. 4,416,638, issued Nov. 22, 1983, which discloses a fuel distribution system including a casing surrounding the upstream portion of a gas feed pipe between the boat transom and the carburetor of the engine. The casing is not connected to the source of fuel and does not surround the entire portion of the fuel pipe located interiorly of the boat.
Attention is further directed to Baltz U.S. Pat. No. 4,722,708 that is assigned to the assignee of the present invention and is herein incorporate by reference. As further described below, the Baltz patent advantageously overcomes the drawbacks of the foregoing Ellis patent. It would be desirable, however, to provide a return path to the fuel source to any fuel that could spill within a housing that surrounds the portion of any fuel conduit located interiorly of the boat. It would be further desirable to prevent fuel flow from the fuel tank into the housing, such as could occur during an overflow condition of the fuel tank. It would also be desirable to provide a marine propulsion system that uses a reliable and user-friendly installation kit that safely and economically allows for relatively quick maintenance and substantially trouble-free operation of the fuel delivery system therein.